QUITO, Ecuador (AP) — A 76-year-old woman who was declared dead at a hospital in Ecuador astonished her relatives by knocking on her coffin during her wake, and the incident has prompted a government investigation into the hospital.

Relatives left the coffin behind and rushed retired nurse Bella Montoya back to the hospital after the wake Friday in the central city of Babahoyo, son Gilberto Barbera told The Associated Press.

“It gave us all a fright,” Barbera said, adding that doctors have said his mother’s situation remains dire.

Ecuador’s Health Ministry said that Montoya was in intensive care Monday at the Martín Icaza Hospital in Babahoyo while the ministry investigates doctors involved in her case. A technical committee has been formed to review how the hospital issues death certificates, the ministry said in a statement.

Montoya initially had been admitted Friday at the hospital with a possible stroke and cardiopulmonary arrest, and when she did not respond to resuscitation a doctor on duty declared her dead, the ministry said.

Barbera said his mother was unconscious when she was brought to the emergency room and that a few hours later a doctor informed him she was dead and handed over identity documents and a death certificate.

The family then brought her to a funeral home and were holding a wake later Friday when they started to hear strange sounds.

“There were about 20 of us there,” Barbera said. “After about five hours of the wake, the coffin started to make sounds. My mom was wrapped in sheets and hitting the coffin, and when we approached we could see that she was breathing heavily.”

Though he and relatives rushed her back to the hospital Friday, she was still in serious condition Monday. She was under intubation, and doctors weren’t giving relatives much hope about her prognosis, Barbera said.

No details have been released about the doctor who had prematurely declared the woman dead.